Lead toxicity remains a major environmental health risk throughout the world. Pakistan and South Asian countries consider phasing-out of leaded gasoline as an adequate measure for control of lead. However, lead deposited in environmental media and maternal bone continues to expose fetuses and children. Our preliminary study in Karachi has shown that approximately 50% of neonates in an urban area of Pakistan had cord blood lead levels (BLL) above10 <g/dL. We assessed sources of lead exposures using questionnaires;however, we were not able to measure lead levels in environmental media. The proposed study, a pioneer study on lead exposure in South Asia, will recruit women delivering infants at one of three tertiary care hospitals in Karachi, Pakistan and will measure lead in environmental media in their homes. The specific aims are: (1) to estimate the mean umbilical cord blood lead level and the proportion of newborns with high cord blood lead levels (>10</dl);(2) to determine sources and levels of environmental lead exposure in children's homes and surroundings;(3) and to identify the major determinants of umbilical cord blood lead level (BLL) including environmental sources and maternal determinants. We will recruit mothers presenting for delivery at the study hospitals, interview them, will collect their blood for BLLs, serum ferritin and hemoglobin, and will collect umbilical cord for lead levels. We will conduct environmental source measurements in homes and surrounding environment. The Centers for Disease Control and Prevention (CDC) will provide technical assistance to interpret and disseminate research findings for national policy makers and public health professionals. This study will contribute to understanding the sources of lead in environment that will provide a basis for which to inform issues of lead abatement and environmental risk reduction in Pakistan and serve as a model intervention for other countries in the region. PUBLIC HEALTH RELEVANCE: Narrative Lead toxicity continues to remain a major environmental health risk throughout the world. Previous research has shown that about 50% of Pakistani children have blood lead levels (BLL) >10 <g/dL. There is growing evidence of an association between children exposed to lead levels and lowered cognitive function, and delinquent behavior in young adulthood. These findings raise concerns about the health of children and of their future potential to be productive members of society in their country and in the world. This study, a pioneer study on lead exposure assessment in a developing country, will contribute to understanding the role of various sources of lead exposure in Pakistan. These data will provide a basis for intervention in Pakistan at the national level that will result in reduction of BLLs in children. The findings of this study also are directly relevant to lead prevention/control programs in other countries in South Asia.